Piston



May 8, 1923.

A. L. NELSON PISTON Filed Oct. 27 1920 anwwtoz Adolph LNelson Patented May 8, 1923.

.ADOLPH L. NELSON, O-F INDIANAPOLIS, INDIANA, ASSIGNOB OF ONE-CLHIRID 'IQ CHARLES S. CRAWFORD, O]? INDIANAPOLIS, INDIANA.

PISTON.

Application filed October 27, 1920. Serial No. 419,938.

To all whom it may concem Be it known that I, ADoLPH L. NELsoN, a citizen ofthe United States, residing at Indianapolis, in the county of Marion and State of Indiana, have invented certain new and useful Improvements in Pistons, of which the following is a specification.

My said invention relates to pistons for engines and particularly for use with internal combustion engines. In such engines a great deal of heat is evolved in the cylinders causing both cylinders and pistons to expand. With cast-iron pistons this expansion is not excessive and they may fit the cylinders fairly closely at all times. With pistons of highly expansible metal, such as aluminum alloy, for example, much more clearance must be allowed, the expansion of the piston being much greater than that of the cylinder.

' Some of .the larger pistons are water cooled in present practice, but most of them are not and as the top of the piston is subjected to very high temperature in use it is necessary that the top and adjacent parts of highly expansible metal pistons should be materially smaller than their cylinders to avoid scoring the cylinders and binding of the pistons in the cylinders. This result of excessive clearance when the engine is cool causes a disagreeable noise known as piston slap.

' As the engine is heated this noise lessens and finally disappears when the clearance of the piston in the cylinder has been sufiiciently reduced. It is an obj ect of my invenvention to eliminate this noise.

It is also an object to provide a construction that will practically prevent leakage 40 of oil past the cylinder head, where it is burned and produces carbon, also to prevent the loss of power by a loose piston pulling the piston rings from the cylinder walls.

Referring to the accompanying drawings,

which are made a part hereof and on which similar reference characters indicate similar P Figure 1 is an elevation of my improved piston,

Figure 2, a central section of the same Figure 8, a section on line 3-3 of Figure 2,

Figure 4:, a view showing a modified form, and

Figures 5 and 6 views showing still another modified form.

In the drawings, 4 represents a piston of any ordinary type and material having a head 5 grooved as usual at 6 for the recepof inverted U-shape from two holes 10 through the piston just above .the rim or flange 11. The holes and slot may be left when the piston is formed, or the holes may be bored and the slot cut in any convenient manner. side only, as shown in Figures 1 and 2, or in both sides as. shown in Figure 4. A flexible portion 12 is thus formed on one side in one form and on both sides in the other, extending from points near its rear end nearly to the head.

The flexible portion has formed therein an internal boss 13, and a similar boss 14 is provided diametrically opposite thereto, said boss 14 being preferably screw-threaded in ternally. A spacer 15 with enlarged heads is mounted in these bosses, a screw 16 engaging the threads in boss 1 1 and being hollowed out to receive one of the heads.

This slot may be formed on one The piston being fully assembled it will now be evident that the diameter of the rigid head at AA is constant save for variations due to temperature. The diameter at C-0 is also constant, and as the rear end of the piston is less exposed to heat this portion varies less in size and may be and usually is larger than at the diameter AA. At

, BB the diameter may be less than taken in line with the piston pin or at CC and greater than at AA if desired, although the provision of slots 9 will permit expansion and contraction of the separated portions of the skirt toward and away from each other to some. extent, the slot thus'becoming narrower and wider as the piston is heated and cooled. But if taken in line with the pin 15 it will be nearly constant, the parts being preferably so constructed that the piston diameter at this point will bear a constant relation to that of the cylinder.

To attain this object I have made the portions 12 flexible and placed a spacer 15 between them preferably made of material that will expand in length at the same rate as the cylinder diameter increases. By now adjusting the screw 16 to push out the flexible part (or parts) to the extent desired, I provide a certain clearance between the parts 12 and the cylinder. As the engine heats up, the cylinder expands, and the rod 15 elongates at the same rate. The flexible parts are less affected by heat than would normally be the case, as they are partially insulated by slot 9.

The rod 15 is at right angles to the piston pin or substantially so and is directly opposed to the piston slap which is due to the movement of the piston from one side of the cylinder to the other, with either the piston pin or the crank pin as an axis. The clearance between the flexible parts 12 and the cylinder being so adjusted as never to be excessive and being practically constant there is no chance for a slap of consequence to occur, and therefore no disagreeable sound resulting therefrom.

Variations of the structure illustrated will occur to those skilled in the art and I do not limit myself to such disclosure, the true scope of my invention being shown by the claims. As an instance of such variation the distance piece or spacer 15 might be cast in place or east integral with the piston and of the same material; also the piston may be formed elliptical at this point as shown in Figures 5 and 6, as the slap occurs on the sides at right angles with the direction of the piston pin, and the design generally may be varied to suit engines of different types without departing from my invention.

Having thus fully described my said invention what I claim as new and desire to Secure by Letters Patent, is:

1. A piston comprising a head and a skirt, the skirt having a flexible portion, spacing means extending transversely of the piston between such portion and the opposite side to limit the movement of said flexible portion and means to adjust said spacing means, substantially as set forth.

2. A piston comprising a head and a skirt, the skirt having a flexible tongue and a single distance piece loosely connected at one end and extending transversely of the piston from the center of said flexible portion to the opposite side, substantially as set forth.

3. A piston comprising a head and a skirt,

, the skirt having a flexible portion, a projection on said flexible portion, a distance piece fitting therein and in a seat on the opposite side to limit the inward movement of the flexible portion, and adjusting means for said distance piece, substantially as set forth.

4. A piston comprising a head and a skirt, the skirt having oppositely placed flexible portions, annular projections on said flexible portions and a distance piece fitting therein to limit the inward movement of the flexible portions, and a screw mounted in an annular projection and engaging the distance piece to adjust the flexible portions, substantially as set forth.

5. A piston embodying a head and a skirt, the skirt having holes for piston pins and having in its side between said holes U- shaped grooves defining a flexible portion in the skirt, spacing means between the flexible portion and the opposite side, and adjusting means to vary the effect of said spacing means, substantially as set forth.

6. A piston embodying a head and a skirt, the skirt having holes for piston pins and having in its sides between said holes U- shaped grooves defining a flexible portion, a distance piece, and a screw engaging said distance piece, substantially as set forth.

7. A piston embodying a head and a. skirt, the skirt having an inverted substantially U-shaped slot extending through the piston wall and forming a flexible portion fast to the rim of the skirt and extending toward the head of the piston and a distance piece made of material differing from that of the piston body connected to said flexible portion at its upper end midway of its sides and also connected to the opposite side of the skirt, substantially as set forth.

8. A piston made of material differing from that of its cylinder, said piston embodying a head and a skirt, the skirt having inverted substantially U-shaped slots between the wrist pin bearings forming flexible tongues extending upwardly from the rim of the skirt, and a single distance piece made of the same material as that of the cylinder and extending between the tongues, whereby the portions of the tongues on either side of said distance piece are freely flexible, substantially as set .forth.

9. A piston embodying a head and a skirt, the skirt having a flexible portion radially spaced from the piston pin bearings and rigid spacing means extending transversely of the piston and loosely connected at one end to said flexible portion, substantially as set forth.

10. A piston embodying a head and a skirt, the skirt having tongues extending toward the head and rigid spacing means extending transversely of the piston between said tongues and loosely connected thereto near their free ends, substantially as set forth.

11. A piston having a head and a skirt, a flexible tongue in the skirt between the piston pin openings, and a distance piece of less expansible material extending across the piston and connected at one end to the tongue, substantially as set forth.

12. A piston formed of a material difl'er- 5 ing from that of its cylinder and having a head and a skirt, said piston being formed of relatively highly expansible material, and said skirt having tongues extending toward the head between the piston pin openings, 10 and spacing means extending between the tongues and formed of the material similar to that of the cylinder, substantially as set forth. I

In witness whereof, I have hereunto set my hand and seal at Indianapolis, Indiana, this 12th day of October, A. D. nineteen hundred and twenty.

- ADOLPH L. NELSON. [11. s.] Witness:

E. W. BRADFORD. 

